This invention relates to a plug-shaped contact element to be connected or fastened in conductor plate bores, preferably in metallized bores, having a connecting portion with two parallel sidepieces which are movable towards one another and with the sidepieces being connected to each other by a resilient, undulating connecting bridge.
It is generally necessary for contact elements of the type which are to be pressed into metallized conductor plate bores and thus establish electrical contact with the bore walls to be such that these contact elements, on the one hand, can be inserted into bores with various diameters, in which case the electrical contact established with the bore wall has to be sufficient and, on the other hand, provides for the exchange of defective contact elements for repair purposes. In this connection the arrangement has to be such that the metallized conductor plate bore is not inadmissibly deformed or damaged when pushing in the contact element.
In a known pin-shaped contact element of the type initially mentioned (for example as in DE-GM No. 81 05 896), a flexible connecting bridge connecting the two sidepieces of the fastening portion is partly plastically and partly elastically flexible. In the known push-in pin, the cross section of the fastening portion can be in the form of an M, N or X.
In the M-shaped version, the legs of the bridge preferably have an angle of approximately 45.degree. relative to the sidepieces and subtend an angle of approximately 90.degree. to each other. The connecting bridge between the two sidepieces can also be W-shaped. In the known push-in pin, the fastening of the connecting bridge to the sidepieces (seen in cross section) is effected from the ends on the interior surface of the sidepieces.
The known push-in pin is generally satisfactorily suited for a one-time push-in into a metallized conductor plate bore. However, because of the sharp edges of the sidepieces touching the metal bore, there is often serious damage to the metal due to the edges piercing the metal. This is true especially in those cases where extremely precise and synchronized bore and pin measurements are not provided. This being the case in that the economic and general production criteria of such contact pins and conductor plate bores does not generally provide for high tolerance levels.
Furthermore, there is uneven edge stress on the contact edges in the known push-in formation in the bore because of the fastening of the connecting bridge onto the ends of the sidepieces which in turn leads to distortion and tipping tendencies of the pin to be pushed in. By the so-caused irreversible damages and deformation of the metallized bore, an exchange, i.e. the removal of the pin from the bore and the insertion of a new pin into the same bore, is often not possible in a satisfactory manner. Also there are frequent contact problems, especially as regards the necessary gas tight, vibration-safe, long term contact.
The present invention has as an object to provide a pin-shaped contact element to be pushed into metallized conductor plate bores, the tolerance levels of which as regards the bore and push-in area measurements are markedly increased, and which provides an even contact pressure on all contact edges in the bore and which offers the possibility of inserting and removing contact elements without damage and substantial irreversible deformation of the walls of the bore, for example, for the problem-free exchange of contact elements for repair purposes. In this connection, a contact element inserted into the same bore using the common tolerances of todays ready-made manufacture technology would provide a friction safe, gas tight long term contact.
This object can be achieved in a technically advanced manner by providing that the connecting bridge is attached approximately in the middle of the interior surface of the sidepieces, that the transitions from the connecting bridge to the respective sidepiece are rounded, and that the edges of the sidepieces having contact with the bore walls of the conductor plate are also rounded.
The invention provides a pin-shaped contact element with a highly elastic push-in area which can be inserted into a conductor plate bore having very different diameters and furthermore, provides assurance that the metal of the bore is not unduly damaged or deformed, so that an exchange of possibly damaged contact elements is possible without any difficulty. Also a vibration-free, gas tight contact is established between the contact element and the metallized bore via four contact zones.
Furthermore, it is not only possible to remove the contact elements from the bore because of the highly elastic push-in area and to insert a new contact element into the same bore, but it is also possible to insert an already previously used contact element into the bore.
An additional advantage of the invention lies in the fact that the strength necessary to push in such push-in elements can be very minimal, making it possible to push in a number of contact elements together with a corresponding isolating body into a conductor plate.
Other features which are considered characteristic of the invention are set forth in the appended claims.
Although the invention is illustrated and described in relationship to specific embodiments, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.